The texture of rehydrated dried potatoes is to a great extent determined by the swelling state of the cell aggregate at the end of the stipulated preparation time. When potato pieces are dried, the volume shrinks during the drying process to approximately 50% of the starting volume. This compression of the cell aggregate makes rehydration more difficult and incomplete reabsorption of the water removed during drying occurs during the rehydration. The prepared product no longer swells to its original shape, the consistency is frequently tough and the larger the potato pieces, the more difficult it is to achieve good rehydration properties.
The object underlying the invention is therefore to provide large-piece dried potato products which exhibit good rehydration properties, rapid and complete rehydration being sought after.
A number of production processes are known for dried potato products which are prepared by subsequent rehydration and cooking.
Abstract of WO 9622029-A discloses a process for producing potato chips. Dehydrated potato pieces, for example potato flakes, are rehydrated to form a paste, which is then extruded.
Abstract of JP 9000196-A discloses the production of potato products by rehydration of dried thinly sliced potatoes.
Coleman, et. al, U.S. Pat. No. 5,486,369 discloses a fried potato product suitable for processing in the microwave. Raw potatoes are sliced into strips, blanched in a solution comprising table salt and sugar, cooked, dried and fried, producing a product having a moisture content of 10 to 40%, which is then packaged and is said to be able to be kept without freezing and sterilization. It can be reconstituted by heating in a microwave oven without using water or sauces.
Stubbs, et. al, U.S. Pat. No. 5,492,704 discloses a process for dehydrating potatoes for the production of hash browns. In this process, small potato pieces, for example elongate grated potato, is coated with a dry mixture which comprises a particulate component, e.g. granular starch or ground potatoes, which ensures the separation of small adjacent potato pieces. The coating is carried out in this case to ensure that the small potato pieces, even after drying, remain separate and do not stick to one another. There is no shaping to large piece potato products before drying. After reconstitution, when heated in the pan, the small potato pieces may stick together.
In contrast therewith, according to the present invention, the potato pieces are shaped before drying to form large-piece potato products. Although they are made up of individual potato particles, the potato pieces are shaped large-piece items not only during, but also after drying and after rehydration, such as French fries, fried potato slices, Rosti corners, potato dumplings, etc.
Surprisingly, it has been found according to the invention that small coated potato particles can be shaped to form large pieces which retain their shape and do not fall apart, but nevertheless have an open structure which ensures good and rapid drying and rapid and complete rehydration. By means of the process according to the invention, a web-like product is obtained which possesses open cavities into which the drying air and the rehydration water can penetrate, although the overall shape is retained. A porous structure which possesses closed pores, such as are formed in the action of baking powder, does not possess the desired properties of the present invention. During the drying of the shaped pieces according to the present invention, the surface dries more rapidly and becomes dimensionally stable, whereas in the interior, the drying takes place more slowly, so that the desired open-pore structure is formed by shrinkage.